This invention relates generally to abrasive blast media and more particularly to recovery systems therefor.
In an abrasive blasting situation, a media, such as sand or plastic, is propelled under air pressure to impact upon a targeted surface. The impact causes the surface to abrade and thereby strips the surface of paint, rust, or other such matter.
The media, once impact has occurred, looses the vast majority of it's momentum and the media, mixed now with debris from the surface, falls onto the floor. This media/debris mixture must be collected and separated so that the reusable media may again be utilized and the debris discarded.
This collection has traditionally taken a variety of approaches, all of which recycle the mixture through the abrasive blasting equipment's own dust collection system.
One method which has been used is a manual shoveling of the mixture from the floor into a hopper which feeds the dust collection system. Although this is effective, it is extremely time consuming and requires the shut-down of the operation during this "clean-up" process. Additionally, many recovery systems are incapable of handling a "slug" of mixture; to compensate, the shoveling action must be paced so as not to exceed the system's capacity.
Several floor recovery hoppers using pneumatic or mechanical conveyance systems have been developed. These systems, built into the floor of the room, permit the falling mixture to pass through to a conveyance mechanism. In some applications, a screw mechanism is used as an auger to move the mixture to the dust collection apparatus.
Although this method is effective, it requires the hopper to be built into the floor itself; often this is not feasible, especially in a retro-fit situation.
To cure the installation problem, a variety of hoppers have been developed which lay on the floor and permit the mixture to be swept up to the collection apparatus. The mixture, once it is swept into the collection apparatus is moved along, typically through pneumatic force, to the dust collection operation.
These devices, although installation is relatively easy, are not always effective and often require much more time than the shoveling solution discussed earlier.
Further, the retro-fit devices of the current art rely upon pneumatic conveyance mechanisms. As such, should the operator sweep a large volume of media/debris into the hopper, the mass of the mixture is usually sufficient to cause the pneumatic conveyance to break-down and operate only marginally.
In practice, this means that the operator gently sweeps the mixture into the hopper, waiting for one portion to be conveyed away before the next load is pushed into the hopper. This is a slow process; all the while, the abrasive blasting operation is waiting for the spent media and debris to be cleared.
It is clear from the foregoing that there is a need for an easy and quick method and apparatus to clear spent media and debris from an abrasive blast site.